Deceleration device of a tape rule

ABSTRACT

A deceleration device of a tape rule is equipped with a speed reduction gear wheel in the tape rule housing. The speed reduction gear wheel is in mesh with a transmission gear wheel of a reel for coiling a measuring tape such that the rotational speed of the reel when retrieving the extended tape is retarded thereby preventing the danger of scratching the user&#39;s finger or damaging the tape itself by abrasion or impingement. Engagement of the speed reduction gear wheel and the transmission gear wheel can be released by operating a flat pusher plate provided on the housing.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a deceleration device of a taperule, in particular, a deceleration device equipped in a tape rulecapable of retarding the retrieving speed of a tape so as to preventdamaging the tape or scratching the user's finger.

[0003] 2. Description of the Prior Art

[0004] A tape rule plays an important role in many fields of engineeringfor measuring size of an object.

[0005] In an conventional tape rule, when retrieving the tape, the userturns a handle bar or a shank emerging out of the tape rule housing torotate a reel accommodated therein and the tape is rewound around thereel. However, it is not ideal to rewind the tape manually with such atime consuming and tedious way. For overcoming the above shortcoming.There has appeared an automatic retrieving tape on the market, soonafterwards, it has been discovered that there are some new problemsbrought up by this new type of tape rule, namely:

[0006] 1. Retrieving the tape with high speed accompanies the danger ofscratching the user's finger due to vibration of the tape.

[0007] 2. Impingement of the tape tip with high speed onto the housingis prone to damage the tape and shorten its lifetime.

[0008] 3. Abrasion of high speed moving tape with the edge of housingcauses of early wearing of the tape.

[0009] In view of the foregoing situation, the inventor of the presentinvention has conducted intensive research based on many years ofexperience gained through professional engagement in the manufacturingof related products, with continuous experimentation and improvementculminating in the development of the ingenious deceleration device of atape rule.

SUMMARY OF THE INVENTION

[0010] It is an object of the present invention to provide adeceleration device of a tape rule capable of preventing the danger ofscratching the user's finger with the high speed retrieving tape.

[0011] It is another object of the present invention to provide adeceleration device of a tape rule capable of preventing theimpringement of the high speed retrieving tape onto the tape rulehousing causing damage to the tape tip.

[0012] It is one more object of the present invention to provide adeceleration device of a tape rule with a simple structure, easy forassembling, and low production cost.

[0013] To achieve these and other aforementioned objects, thedeceleration device of the present invention comprises a tape rulehousing, a reel, and a deceleration unit. Wherein a through hole for anaxle is provided at the reel center portion and a transmission gearwheel is coaxially fitted into the reel. The housing is formed of anupper housing and a lower housing, and an axle is passing through thecenter portion of the upper housing. A speed reduction gear wheel of thedeceleration unit is fitted in an aperture provided for the upperhousing and in mesh with the transmission gear wheel of the reel suchthat the reel can rotate 360° about the axle to rewind the tape into thetape rule housing with a reduced speed thereby avoiding possible injuryto the user or the tape rule itself.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For fuller understanding of the nature and objects of theinvention, reference should be made to the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

[0015]FIG. 1 is an exploded view of the deceleration device of a taperule according to the present invention;

[0016]FIG. 2 is a three dimensional view of the deceleration device of atape rule according to the present invention;

[0017] FIGS. 3(A) and 3(B) are illustrative views showing the operationof the deceleration device according to the present invention;

[0018]FIG. 4 is an exploded view of the deceleration device of a taperule in another embodiment of the present invention;

[0019]FIG. 5 is a three dimensional view of the deceleration device of atape rule in another embodiment of the present invention; and

[0020] FIGS. 6(A) and 6(B) are illustrative views showing the operationof the deceleration device in another embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0021] Referring to FIGS. 1 and 2, it will be seen that the decelerationdevice of the present invention comprises a tape rule housing 1; a reel2; and a deceleration unit 3. The tape rule housing is composed of anupper housing 12 and a lower housing 11. An axle 121 is erected on thecenter portion of the upper housing 12 through a center hole 22 of thereel 2, and a transmission gear wheel 21 is coaxially fitted to the real2. By so the reel 2 can rotate about the axle 121 in the housing 1 toextend or retrieve a measuring tape 4. The transmission gear wheel 21 isthen covered with the upper housing 12.

[0022] The kernel of the deceleration unit 3 is a speed reduction gearwheel 31 which has tapped holes 32,33 provided at two sides thereof.

[0023] For assembling, the speed reduction gear wheel 31 is set up inthe upper housing 12 via an aperture 122 formed nearby the axle 121, andis in mesh with the transmission gear wheel 21 of the reel 2, thedeceleration unit 3 is engaged with the upper housing 12 on its outersurface thereof by screws 5 after aligning the tapped holes 32 and 33 onthe deceleration units 3 with the corresponding tapped holes 124 and 123on the upper housing 12 respectively.

[0024] Meanwhile, the deceleration unit 3 may be operated with oilpressure, or pneumatic pressure, or by other mechanical means.

[0025] Referring to FIGS. 3(A) and 3(B), in which the operationprinciple of the deceleration device is illustrated. Since thetransmission gear wheel 21 for the reel 2 is in mesh with the speedreduction gear wheel 31 of the deceleration unit 3, the rotational speedof the reel 2 is retarded by the speed reduction gear wheel 31 so thatthe tape 4 can be retrieved with a rather low speed thereby avoiding thecollision of the tape tip 41 with the housing 1 or abrasion of the tapesurface 42 and prolonging the lifetime of the tape rule.

[0026] For understanding another embodiment of the present invention,reference should be made to FIGS. 4 and 5. The deceleration device inthis embodiment comprises a tape rule housing 6; a reel 2; and adeceleration unit 7. The tape rule housing 6 is composed of an upperhousing 62 and a lower housing 61. An axle 624 is erected on the centerportion of the upper housing 62 through a center hole 22 of the reel 2,and a transmission gear wheel 21 of the deceleration unit 7 is coaxiallyfitted into the reel 2. By so the real 2 can rotate about the axle 624in the housing 1 to extend or retrieve a measuring tape 4. Thetransmission gear wheel 21 is then covered with the upper housing 62.

[0027] A flat puser plate 74 with a plurality of slip stop stripes 741thereon is provided on the outer surface of the deceleration unit 7, anda speed reduction gear wheel 71 is installed beneath its inner surfacethereof. One terminal of the deceleration unit 7 has a through hole 72,while the other terminal thereof is formed into a hook 73.

[0028] For assembling, the speed reduction gear wheel 71 is set up inthe upper housing 62 via an aperture 621 whose size being slightlylarger than that of the speed reduction gear wheel 71 and is in meshwith the transmission gear wheel 21 of the reel 2. After aligning thethrough hole 72 with a circular hole 622 provided on the upper housing62, and penetrating a hinge pin 8 therethough, the deceleration unit 7may be hinged to the outer surface of the upper housing 62 anddisplaceable to and fro thereon by operating the flat pusher plate 74.The hook 73 at one terminal of the deceleration unit 7 is used to hookonto a post 623 provided on the outer surface of the upper housing 62nearby the aperture 621 for fixing the deceleration unit 7 stably at itsposition.

[0029] Meanwhile, the deceleration unit 7 may be operated with oilpressure, or pneumatic pressure, or by other mechanical means.

[0030] Referring to FIGS. 6(A) and 6(B), in which the operationprinciple of the deceleration device in this embodiment is illustrated.For rapid retrieval of measuring tape 4, reference should be made toFIG. 6(A) in which the flat pusher plate 74 is pushed back a prescribeddistance so as to disengage the speed reduction gear wheel 71 from thetransmission gear wheel 21 thereby releasing the reel 2 from retaringforce of the deceleration unit 7. On the other hand, for Retrieval ofmeasuring tape 4 with a reduced speed, reference should be made to FIG.6(B) in which the flat pusher plate 74 is pushed forward a prescribeddistance so as to engage the hook 73 of the deceleration unit 7 with thepost 623 on the outer surface of the upper housing 62 and mesh the speedreduction gear wheel 71 of the deceleration unit 7 with the transmissiongear wheel 21 of the reel 2 thereby putting the rotation of reel 2 undercontrol of the retarding force of the deceleration unit 7.

[0031] It emerges from the description of the above embodiments that theinvention has following noteworthy advantages, namely:

[0032] (1) The deceleration device of the present invention is able toprevent the danger of scratching the user's finger by the taperetrieving in high speed.

[0033] (2) The deceleration device of the present invention is able toprevent damage to the tape tip caused by impringement of the high speedretrieving tape into the housing or abrasion of the tape itself andprolong the lifetime of the tape rule.

[0034] Although the invention has been described in terms of preferredembodiments, it is apparent the numerous variations ant modificationsmay be made without departing from the true spirit and scope thereof, asset forth in the following claims.

What is claimed is:
 1. A deceleration device of a tape rule comprising:a housing composed of two sub-housings, an axle being erected on thecenter portion of one of the two sub-housings, and an aperture beingprovided nearby said axle; a reel with a through hole at its centerthereof, said axle being penetrating via said through hole such thatsaid reel being rotatable about said axle in said housing driven by atransmission gear wheel coaxially fitted to said reel such that saidreel is able to extend a measuring tape coiled on it, or retrieve theextended tape back; and a deceleration unit whose speed reduction gearwheel being set up in said sub-housing via said aperture and being inmesh with said transmission gear wheel of said reel for retarding therotation of said reel.
 2. A deceleration device of a tape rulecomprising; a housing composed of two sub-housings an axle being erectedon the center portion of one of the two sub-housings, and an aperturebeing provided nearby said axle, while a post and a circular hole isprovided on the outer surface of said sub-housing; a reel with a throughhole at its center thereof, said axle being penetrating via said throughhole such that said reel being rotatable about said axle in said housingdriven by a transmission gear wheel coaxially fitted to said reel suchthat said real is able to extend a measuring tape coiled on it, orretrieve the extended tape back, and a deceleration unit with a speedreduction gear, one terminal of said deceleration unit has a throughhole, while the other terminal thereof is formed into a hook; said speedreduction gear wheel is set up in said sub-housing via said aperture andis in mesh with said transmission gear wheel of said reel for retardingthe rotation of said reel, after aligning said through hole with saidcircular hole provided on said sub-housing, and penetrating a hinge pintherethough, said deceleration unit is hinged to the outer surface ofsaid sub-housing and is displaceable to and fro thereon so as to engageor disengage said speed reduction gear wheel with said transmission gearwheel.
 3. The deceleration device of claim 1, wherein said decelerationunit is tightly engaged with said sub-housing by screw combining twotapped holes provided at both sides of said sub-housing near saidaperture with two tapped holes provided at both sides of saiddeceleration unit.
 4. The deceleration device of claims 1 and 2, whereinsaid deceleration unit is operated with oil pressure or pneumaticpressure, or by other mechanical means.
 5. The deceleration device ofclaim 2, wherein said aperture formed on said sub-housing has a sizeslightly larger than that of said speed reduction gear wheel forallowing room for said speed reduction gear wheel movable to and frotherein.
 6. The deceleration device of claim 2, wherein a flat pusherplate is provided for said speed reduction gear wheel so as to push saidspeed reduction gear wheel movable to and fro. Wherein the surface ofsaid flat pusher plate has a plurality of slip-stop striples.
 7. Thedeceleration device of claim 2, wherein said post and said circular holeare correspondingly formed on said sub-housing nearby said aperture. 8.The deceleration device of claim 2, wherein said hook provided at theterminal of said deceleration unit is used to hook onto said postprovided on the outer surface of said sub-housing so as to fix saiddeceleration unit stably at its position.